WASHINGTON
— If a teenager in Maine wants to buy a pack of cigarettes in a store, the teen is required to prove he or she is at least 18 years old. No proof of age, no cigarettes. That's the law.

But what if an underage teen logs onto the Internet and orders several cartons of cigarettes for home delivery?

That's the scenario Maine's Tobacco Delivery Law was designed to prevent. The law requires the shipping company's delivery driver to verify that the individual who ordered and is receiving the cigarettes is, in fact, 18 or older.

The issue arrives Wednesday at the US Supreme Court, where the justices must decide whether Maine's effort to regulate tobacco sales on the Internet is preempted by a federal law that bars individual states from interfering in the operations of interstate shipping and transport companies.

The case, Rowe v. New Hampshire Motor Transport Association, is seen by the business community as an important test of federal power to insulate national businesses from a burdensome patchwork of state regulations.

"Without a doubt, states may prohibit tobacco sales to minors and punish retailers who violate the prohibition," says Washington lawyer Evan Tager in a friend of the court brief filed on behalf of the American Trucking Association and the US Chamber of Commerce. "What they may not do, however, is regulate [motor] carriers' services and distribution procedures on a varying state-by-state basis in an effort to conscript them into the policing and enforcement of such laws."

At least 39 states restrict the sale of tobacco over the Internet as a means of keeping cigarettes away from minors. Some states ban Internet cigarette sales entirely, while others, like Maine, have tried to confine Internet tobacco sales to adults.

The challenge is sorting the minors from the adults. "If the person is not walking into a store, how do you do age verification?" asks Kathleen Dachille of the Baltimore-based Legal Resource Center for Tobacco Regulation, Litigation & Advocacy.

Shipping companies say that requiring their drivers to conduct age verification for each tobacco package is onerous and will stall the quick delivery of all packages.

The companies are capable of conducting age verification, says Ms. Dachille, who filed a friend of the court brief on behalf of several antismoking groups. "When I am sending something by FedEx there are a whole host of things I can ask them to do. There are different ways I can ship it, different rules about who can accept it, what the signature requirement must be, and who it can be left with," she says. "They already offer those sorts of premium services to their customers, so while it may create some level of burden they can certainly charge their customers for that."

At the heart of the case is a clash between congressional deregulation of the shipping industry and efforts by the individual states to protect their children from the harms of smoking.

The deregulation was authorized in the Federal Aviation Administration Authorization Act of 1994. The FAAAA preempts any law passed by a state that is "related to a price, route, or service" of a shipping company.

In 2003, three trucking trade associations from New Hampshire, Massachusetts, and Vermont sued Maine Attorney General G. Steven Rowe arguing that the Maine tobacco law violated industry protections in the FAAAA.

The First US Circuit Court of Appeals in Boston agreed and struck down most of Maine's tobacco statute in May 2006.

Lawyers for the trucking associations are urging the high court to embrace a broad interpretation of preemption under the FAAAA.

"The preempted nature of the provisions is most obvious when one considers what the effect would be if several – or perhaps 50 – states enacted similar laws regulating a variety of commodities," writes Washington lawyer Beth Brinkmann in her brief to the court on behalf of the three trade associations. "That patchwork of varying requirements on the transportation and delivery services of carriers would be cost prohibitive and would bring the cargo carrier industry to a standstill."

Many state officials hold a different view. "Unless the court rejects [the industry's] limitless view of preemption, the most effective and practical tool that states employ to restrict illegal sales of tobacco to children over the Internet will be undermined," writes California Deputy Attorney General Laura Kaplan in a friend of the court brief on behalf of 38 states, the District of Columbia, and Puerto Rico.

The Maine attorney general's office argues in its brief that Congress's preemption is meant to invalidate state economic regulations that affect access to markets, not state efforts to protect public health and safety.

"Maine has the sovereign authority to protect its children by regulating how dangerous substances may be delivered in the state," says Deputy Attorney General Paul Stern in Maine's brief to the court.